SEATTLE -- An Army appeals court has halted the prosecution of one of five soldiers charged with killing Afghan civilians for fun earlier this year, taking the unusual step after his lawyer argued that the Army's refusal to make gruesome photographs public violated his client's right to an open trial.

Pfc. Andrew Holmes, of Boise, faced a preliminary hearing last week to determine whether there's enough evidence to send his case to a court martial. His lawyer, Dan Conway, objected because the Army barred him from showing photographs which he says help prove that his client did not kill one of the civilians. Conway said that 10 or so pictures of the victim do not appear to show any bullet wounds that could have come from the heavy machine gun Holmes was carrying.

Conway asked the Army Court of Criminal Appeals to step in and halt the proceedings or order the Army to let him present the photos. The court ordered a stay Friday and told the Army to respond to Conway's arguments within 20 days. Conway gave a copy of the order to The Associated Press on Saturday.

"We're very pleased the Army Court of Criminal Appeals will consider this," Conway said. "It's a very serious issue when an American soldier is denied his constitutional rights to a public trial and to present exculpatory evidence."

The Army has kept a tight lid on dozens of photos seized from soldiers in the Joint Base Lewis-McChord infantry platoon because it fears their publication could provoke violent anti-American backlash around the world. Some of the photos depict badly mangled corpses and soldiers posing with dead bodies, according to those who have seen them.

Maj. Kathleen Turner, a spokeswoman for Joint Base Lewis-McChord near Seattle, where the accused soldiers are stationed, has called the images "highly sensitive."

Defense attorneys are not allowed to have copies of the photos but may view them at an office at the base. The Army's investigating officer, who will make a recommendation about whether to send the case to court martial, also has access to the photos.

Eugene Fidell, president of the National Institute of Military Justice and a military law lecturer at Yale University, criticized the Army's attempt to keep the photos out of the public eye. He also said it's rare for the appeals court to grant a stay of proceedings, even though defense attorneys request them frequently.

"Stays do not grow on trees," Fidell said Saturday. "You're talking about suspending the trial process, and that's a huge inconvenience to the government."

Holmes is charged with conspiracy, premeditated murder, and other crimes stemming from the deaths of three civilians in Kandahar province early this year. He is charged with directly participating in only the first killing while on a patrol in January, but faces conspiracy charges in the second and third deaths as well.

Soldiers in the platoon say Staff Sgt. Calvin Gibbs and Spc. Jeremy Morlock created a "kill team" and discussed how they could get away with killing civilians by making them appear to be combatants.

Gibbs insists all the three killings were legitimate, while Morlock gave investigators extensive statements describing the plot. Much of the Army's case is based on Morlock's statements.

Holmes acknowledges that he heard Gibbs and others discuss killing civilians, but says he didn't know he was shooting at a civilian when Morlock shouted about a grenade and ordered him to open fire.

Holmes told the investigating officer during a hearing Monday that he "did not commit murder."

One witness said it appeared that Holmes' shots missed the man, but Holmes could be found liable if he knowingly shot at the civilian without cause. Conway said he needs to provide copies of the photos to a forensic pathologist who could opine about the cause of the victim's death.